GB576316A - Castor oil products and preparation of same - Google Patents

Abstract

A product suitable as a varnish oil is obtained by mixing castor oil with one or more polybasic acid esters of an unsaturated alcohol, which unsaturated alcohol contains an olefinic linkage between two carbon atoms, one of which is directly linked by a single bond to the carbinol group, and heating the mixture in the presence of a dehydration catalyst so that dehydration of the castor oil with simultaneous heat bodying of the mixture is effected. Suitable polybasic acid esters are diallyl carbonate, diallyl oxalate, dimethallyl oxalate, diallyl succinate, diallyl adipate, dimethallyl carbonate, dimethallyl succinate, dimethallyl adipate, diallyl phthalate, diallyl maleate, diallyl terephthalate, diallyl diglycollate, triallyl citrate, di-(b -chlorallyl) succinate, di - (b - chlorallyl) phthalate, di - (methylvinyl carbinyl) adipate, di-(methylvinyl-carbinyl) phthalate, dicrotyl mesaconate, dicrotyl phthalate, dicinnamyl glutarate, dicinnamyl phthalate, triallyl borate, triallyl phosphate, trimethallyl borate, tricinnamyl phosphate, allyl methallyl phthalate, allyl cinnamyl adipate, dimethallyl crotyl borate and diallyl monobutyl citrate. Dehydration catalysts include a number of metal sulphates, bentonite, p-toluene sulphonic acid, tungsten trioxide, phosphorus pentoxide, sulphuric acid, boron oxide, molybdenum oxide, kaolin, ammonium acid sulphate, phthalic anhydride and maleic anhydride. In examples: (a) castor oil is heated with diallyl phthalate in the presence of sodium bisulphate; (b) for comparison purposes, dehydrated castor oil is heated with diallyl phthalate; and (c) maleic alkyd varnishes and ester gum varnishes are prepared from the products of (a) and (b). Coating compositions may be prepared from the varnish oils by thinning with naphtha or aliphatic hydrocarbon thinners and adding such ingredients as lead, cobalt or manganese driers, pigments and plasticisers. Varnishes may be prepared from the varnish oils by cooking with natural or synthetic resins such as maleic or other alkyd resins (including rosin-modified alkyd resins), ester gum, phenolic resins, modified phenolic resins, rosin-modified ureaaldehyde resins, coumarone-indene resins, melamine-urea-formaldehyde resins, rosin and rosin derivatives like polymerized and partially hydrogenated rosin. The varnish compositions may contain stains, dyes, pigments, mineral thinners or other hydrocarbons, and driers such as lead, cobalt or manganese linoleates or the corresponding resinates or naphthenates or mixtures thereof. The unsaturated esters of polybasic acids used in the preparation of the varnish oils can be made in the usual manner from the appropriate alcohol. Specific preparation details, however, are given in some cases: (i) trimethallyl borate and tricinnamyl phosphate can be prepared by the methods described for triallyl borate and triallyl phosphate respectively in Beilstein's "Handbuch der organischen Chemie," Vol. I, page 439; (ii) allyl methallyl phthalate may be prepared by heating methallyl alcohol with phthalic anhydride to produce monomethallyl hydrogen phthalate and then esterifying with allyl alcohol in the presence of p-toluene sulphonic acid and benzene; (iii) allyl cinnamyl adipate may be prepared by forming monocinnamyl hydrogen adipate from cinnamyl alcohol and adipic anhydride and then esterifying it with allyl alcohol; (iv) diallyl monobutyl citrate may be prepared by forming monobutyl dihydrogen citrate from butyl alcohol and citric acid and then esterifying it with allyl alcohol; and (v) dimethallyl crotyl borate may be prepared by reacting together methallyl alcohol, crotyl alcohol and boric anhydride or acid. Specifications 547,854 and 576,317 are referred to.